functions: let `cloud-init clean` inform about NM

live-build/functions

@@ -999,6 +999,17 @@ system_info:
     renderers: ['network-manager']
     activators: ['network-manager']
 EOF
+
+        # Allow cloud-init clean to inform of strict network-manager config
+        mkdir -p chroot/etc/cloud/clean.d
+        cat <<EOF > chroot/etc/cloud/clean.d/99-installer-use-networkmanager
+# Inform clone image creators about strict network-manager cfg for cloud-init
+if [ -f /etc/cloud/cloud.cfg.d/99-installer-use-networkmanager.cfg ]; then
+  echo "WARNING: cloud-init network config is limited to using network-manager."
+  echo "If this is undesirable: rm /etc/cloud/cloud.cfg.d/99-installer-use-networkmanager.cfg"
+fi
+EOF
+        chmod +x chroot/etc/cloud/clean.d/99-installer-use-networkmanager
     else
         echo "==== NetworkManager not installed ===="
     fi